


The Realness of Romance

by lucadumpster



Series: Stay By My Side [1]
Category: Dr. STONE (Anime), Dr. STONE (Manga)
Genre: Anal Fingering, Blow Jobs, Bottom Asagiri Gen, Confessional Sex, First Kiss, First Time, Fluff, Fluff and Smut, Love Confessions, M/M, Mutual Pining, Porn With Plot, Porn with Feelings, Shameless Smut, Smut, They’re rly in love wow, Top Ishigami Senkuu, senku is a disaster gay
Language: English
Status: Completed
Published: 2021-03-08
Updated: 2021-03-08
Packaged: 2021-03-14 03:06:53
Rating: Explicit
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 4,223
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/29910486
Author URL: https://archiveofourown.org/users/lucadumpster/pseuds/lucadumpster
Summary: Love wasn’t even a millimeter interesting to Senku.Except for when it came to Gen.
Relationships: Asagiri Gen & Ishigami Senkuu, Asagiri Gen/Ishigami Senkuu
Series: Stay By My Side [1]
Series URL: https://archiveofourown.org/series/2202252
Comments: 8
Kudos: 105





	The Realness of Romance

**Author's Note:**

> Sorry if this doesn’t completely match up w the plot of the anime/manga. I’m trying my best ;-;

It had never really occurred to Senku that he could fall in love. Not that he didn’t believe in it (his best friend Taiju was a great example of the realness of romance). He just didn’t believe there was some person out there that could catch his interest and hold it. Science had been the only thing that preoccupied his mind. It was the single most aspect in his life he felt enamored by; everything else pales in comparison. 

The fact that he had been petrified, encapsulated in stone for 3,700 years didn’t help his thoughts on love. What were the chances he would ever find that in this world? None, is what he thought. This was a time of survival, not illogical things that numbed your brain and made you talk stupid. 

There had been a slight hiccup in his thought process as of late, though. Mentioned hiccup was a man with black and white hair who had a taste for causing trouble. Senku knew he shouldn’t get involved with someone so… self-fulfilling, and he tried constantly to place boundaries between them, but Asagiri Gen didn’t like to stay inside the lines. In fact, he liked to push them, tip-toeing on the edge to see how far he could go. Senku had to appreciate Gen’s calculations. Science always needed people who tested limits. 

But, Senku was starting to feel that his admiration was less about science and was something else entirely. 

Senku started to waver on his intentions when Gen was attacked by Magma. Senku would never admit it to anyone, but he was the one who stayed up with the injured mentalist, caring for his wounds and grimacing at his periodic whines of pain. Senku wasn’t one to cater to anyone else’s needs. He did things for other people when he felt like it. But, there had been something about Gen’s broken body and pale face that made his blood run cold. 

That night, Gen whispered something quietly on his side of the room under many blankets, his slender shoulders and back exposed to the scientist. Senku had rushed over, dropping to Gen’s side, not thinking about how close he was to the mentalist’s pasty face. Even like that… even so sick… even though he could die… Senku couldn’t help but feel enraptured by his half-lidded indigo eyes and the way his two-toned bangs stuck to his forehead with sweat. 

‘This is exhilarating,’ he thought immediately. His mouth went dry and his jaw slackened, jerking away the hand that braced him on the other side of Gen. He only ever said that about science. Why was he applying it to the closeness of another human being? Senku had never been one for physical contact. It made him extremely nervous and uncomfortable; people’s skin was too hot and sticky for his liking. Though, this nervousness, this uncomfortably, had nothing to do with disgust. 

It didn’t make any sense.

After Gen regained his health, Senku treated him just like everyone else. Maybe a bit more harshly since the mentalist complained constantly and asked invasive questions. But, Senku couldn’t bring himself to tell the man to fuck off. In all honesty, Senku looked forward to the days he spent with Gen. It was nice to have someone else around from the pre-Stone Age times. Comforting, even. He was able to reminisce about things from back then, no matter what it was, no matter how complicated. Gen seemed to miss regular conversation as well since he never interrupted Senku while he dumped heaps of information he had stored in his massive brain. The scientist had a hard time reeling himself in when he started on the topic of science, his passion taking over. 

It would be a lie if Senku said his heart hadn’t filled to bursting when Gen and the other people of the village gifted him a telescope for his birthday. He knew that everyone had helped in making it, but he also knew it was Gen who had proposed the idea in the first place. Yes, Senku had fulfilled the wish Gen had whispered that night about cola, but building a telescope? Without Senku finding out or asking for his help? That was on another level. 

Both of them had played it off as cringy and not a big deal, but Senku knew it was more than that. It was Gen saying, “I’ve been paying attention this entire time. I understand you.” 

Senku had to control every screaming instinct that flared inside him not to stroke the side of the mentalist’s beautiful face with the back of his hand. The moment had been perfect and the way the moon shined down upon them was infinitely romantic, even to the emotionally inept scientist. He thought for a second that even if they hadn’t been sealed in stone for thousands of years, if they were just normal young adults, Senku would’ve brought Gen to see the stars anyway just to have the chance to see them reflect gorgeously in his irises.

Love wasn’t even a millimeter interesting to Senku. Except for when it came to Gen. 

🧪 • 🧪 • 🧪 • 🧪 

As he did every evening, Senku sat up in the observatory, sketching ideas for their next step in claiming the earth back, oil lamps placed in various locations above for optimal light, the revolving roof closed for the night. This was the only time he could escape the rowdy villagers who crowned him their new chief. He cared a lot for these people and they believed in him unconditionally. A sentimental part of Senku made him smirk as he thought about how much of a family these individuals had become.

He scratched furiously at a piece of crude leather that served as paper with a charcoal pencil, furrowing his brows. How would this fit together? Was it a plausible idea? Did they have the materials? No matter how many questions, no matter how difficult, Senku worked on. There was nothing more satisfying than figuring out an answer to a question no one else but him could figure out. When all else failed, science was there to scoop him back up and right him on his feet. 

“Senku-chan!” An all-too familiar voice spoke next to his ear. The scientist jumped in his seat, scattering his work on to the floor. 

“Oh, I’m sorry! Let me get that for you!”

“No, no. It’s okay.” 

Gen and Senku both reached down at the same time, brushing hands. Senku recoiled, fearful of what might happen if he touched the mentalist for too long. How would that affect him? He couldn’t be more of a blushing mess than he already was. 

The mentalist didn’t think twice about the awkward mishap or didn’t let it show as he picked up Senku’s projects. He dipped into a slight bow as he handed the leather sheets over. 

“There’s no need to be so formal. You’re older than me, anyway,” Senku said as he received the notes and set them back on his desk. 

“I think I should be respectful to the new chief,” Gen said with a mischievous smile lighting his face. 

Senku sighed and pinched the bridge of his nose, squinting his eyes shut. Just hearing Gen’s voice made his head spin out of control. 

“What did you need?” 

The next words Gen spoke were in a hushed voice next to Senku’s unbelievably warm ear. “Who said I needed something? Sometimes I like to watch you do your whole science thing. In its own way… it’s quite beautiful.” 

His heart began to do that thing where it clenched up and ran ten billion percent faster than what should be humanly possible. Senku’s face kept heating up. He couldn’t take this. 

“Don’t just say things like that,” Senku wheezed, nudging Gen with his shoulder, refusing to unglue his stricken gaze from his notes. 

Gen tilted his head to the side, a quizzical look across his face. “Why?” 

“It’s embarrassing,” Senku whispered, sounding more like a question than an answer. 

“I could never be embarrassed by the things I find interesting. I know you feel the same,” Gen laughed, taking a step back, his hands clasped together under his purple sleeves. 

“I-I don’t have time to be talked to or watched. I need to focus.” Senku knew it was a pisspoor excuse. Everyone knew (including Senku, himself) that he loved when people paid attention as he delved into the world of science. It was his area of expertise and he had a cocky streak when it came to his favorite topic. 

Gen’s usually controlled face lost its composure, his easy smile falling. He pressed his small lips together, fiddling with his thumbs inside his sleeves. Senku felt his stomach clench, but he knew he had already eaten that day. Could it be possible his organs were failing? Did he eat something bad? A voice, a very logical one, replied no.

“I’ll go. I’m sorry to have bothered you. I’m selfish, I know,” the mentalist chuckled half heartedly. He turned to go, his shoulders sagging in a way he didn’t want the scientist to see. 

Something in that look, something in that waver in his voice, something in the way he hung his head as he walked away made Senku want to scream or break something. It was like an experiment he had been working on for a long period of time, logging in major hours and brain time, had failed. The feeling was like glass in his skin and chemicals in his eyes. It was beyond agonizing. 

“Wait.” Senku shot out of his seat, grabbing ahold of Gen’s shoulder. ‘God, he’s so warm,’ Senku thought as his fingers pressed against the fabric of the mentalist’s clothing.

Now, it was Gen’s turn to be surprised. His eyes were wide, his lips parted, and his chest heaved a bit. 

“What’s gotten into you?” Gen asked, trying to laugh, but it came out as a short, hysterical sound. 

“I don’t know. I really don’t know,” Senku said. It occurred to him that this was the first time those words had ever been spoken by him since awakening and establishing the Empire of Science. Even before the Stone Age, Senku never admitted ignorance out loud. He knew he must look and sound completely out of character judging from Gen’s worried expression, his short black eyebrows furrowing. 

Senku’s body moved without any prompt, yanking the mentalist towards him by his upper arm. He felt like he might combust if he kept quiet any longer; felt like his heart might fail if Gen left without knowing how he affected Senku’s every thought. How he made him believe that even the most emotionally unavailable could fall in love. 

“Gen, I-.”

Senku didn’t get a chance to finish before Gen closed the space between them, placing a small palm on Senku’s chest, his eyes gently fluttering closed as he pressed his lips to the scientist’s. 

Senku thought love might have caused The Big Bang. Nothing else could’ve created something out of nothing like this feeling did. 

He didn’t realize just how much emotion he had been holding back until Gen was pressed up against Senku’s desk, his hand gripping the edge, while both Senku’s hands ran feverishly along Gen’s scalp and cupped the base of the mentalist’s head. 

“Slow down a bit,” Gen hummed against Senku’s hungry mouth. “I’m not going anywhere.” 

Those were the words Senku needed to hear above all else. Gen wasn’t going to betray the scientist and his village. He wasn’t doing this only because Senku wanted it. He wasn’t going to suddenly turn into stone again. He wasn’t going anywhere. 

“Is that a promise?” 

Gen giggled a bit and Senku pulled his face away from the mentalist’s, a self-conscious heat coursing across his skin. Had he done something wrong? 

“I never imagined I’d ever hear something so naive from you, Senku-chan,” Gen continued to chuckle, his head resting completely in Senku’s cradled hands. The mentalist’s expression softened, one of his hands sliding easily up the scientist’s back. His eyes continued to flicker from Senku’s wide red eyes to his full lips. 

“Of course I promise. Being by your side has been my plan all along,” Gen whispered, bringing his own blushing face towards Senku’s. Their lips connected again, more seamlessly this time. Senku had never allowed someone to be this close to him before, much less kiss them. The scientist almost asked himself why he had waited so long as Gen slid his tongue into Senku’s parted lips, but that was obvious at this point. He had waited to find someone who could push the limits of his sanity and rival for a place in his heart. Not just anyone would do. They had to be up to par with his first love: science. 

And Gen was the first person to test those boundaries that had been put in place even before Senku was born. 

“How long?” Senku was tugging at the hair that grew at Gen’s nape, enjoying how soft it was between his fingers. “How long has it been since you made that choice?” 

“Since I saw your time of awakening carved into that cave wall. It started out as admiration. I knew your intelligence would out-match Tsukasa’s thirst for blood. I needed to find you, no matter how difficult, no matter how dangerous, no matter how many times I had to leave the village to keep the enemy unalarmed. I was going to do anything to be by your side,” Gen explained in between kisses. What was with this overwhelming feeling that clouded Senku’s judgement and made his insides liquify? Could another human’s presence really affect him in this way? 

For the first time, Senku forgot about his questions and simply let his emotions take over, lifting Gen up onto the desk and pulling his legs up to wrap around his waist. Gen wasn’t much shorter than Senku, but surprisingly, his body was lighter; muscle mass not as defined as the scientist’s. It was a tiny detail, but it was ten billion percent more enticing than anything he’d ever seen or experienced before. 

“I’m… I’m glad you stayed. I’m glad that I can… spend time with you,” Senku sputtered just as Gen began unbuttoning his high-collared shirt. The scientist noticed that even though Gen was projecting himself as confident, his small hands trembled trying to slip the buttons out of the holes. 

Instinctively, Senku gently pulled the mentalist’s fingers from the troublesome clothing, holding his hand in his own. Gen looked up, eyes wide and flickering with light from the lamps above. 

“We don’t have to if you don’t want to,” Senku said softly, his own nervousness making him shake. 

“I’ve wanted to do this with you since you took care of me when I was attacked. If I had had the strength, I would’ve kissed you then,” Gen said, a coy smile pulling his lips up. 

A bit frustrated, Senku asked, “Why haven’t you said anything?” 

Gen’s face became soft again, his eyes resolved. “You’re in love with science, Senku-chan. I thought I never stood a chance. Just being by your side and watching you work was enough for me. I would’ve waited another 3,700 years for you.”

They both peered into each other’s eyes, a weightlessness over both of them. Gen slowly began unbuttoning himself again, his hands slightly less shaky. Once all the buttons were undone, the mentalist shrugged the garb off along with his purple robe, bashfully looking away as his bare chest was exposed. 

Senku bent his head down and brushed his lips against Gen’s pale skin, earning a sharp inhale from the mentalist. They both must have been completely touch starved after centuries of being comatose. The scientist began planting tentative kisses along Gen’s collarbones and up his slender neck, testing to see if he could get the mentalist to make those pretty sounds that came with intimate touch. He was quickly rewarded with quiet gasps for air and hips that didn’t want to stay still. 

The scientist dragged his kisses from Gen’s fragile chest to the soft skin of his belly to the dark hairs below his navel. He was so delicate and smelled like firewood and the wilderness with a hint of something sweet like flowers beneath the harsher scents. It was driving Senku’s brain mad. 

Senku drifted his hand from Gen’s ribs down to the crotch of his tan leggings, surprising himself to find the mentalist was just as aroused as Senku. The brush of fingertips above fabric made the slight curve underneath twitch. Gen could barely stifle a moan as Senku did so, bucking his hips forward and curling his toes. 

“May I take these off?” Gen asked, breathlessly. Senku looked up at the man sitting on the table, chest rising and falling erratically and his eyes a combination of love and lust. Senku smirked, pulling at the waistband of the leggings and Gen slipped them off, revealing the thing the scientist never thought he’d get a chance to witness. With how hard he was, it slapped lightly against his skin and made both of them blush. 

“It’s not as big as mine,” Senku said absently, his voice softer than usual. 

Gen rolled his eyes and folded his arms across his chest. “Great observation, smart ass.” 

Quickly trying to backtrack from his insensitive comment, the scientist waved his hands up and exclaimed, “I-I didn’t mean anything by it! I w-was just… surprised. I didn’t know who-“

“Would end up being the top and who would be the bottom?” Gen finished for Senku, suddenly curious. 

Now it was time for Senku to flush and look away abashedly. “I never thought about it like that. I thought it would come naturally when the time came, I guess…”

Gen giggled and ran a hand through Senku’s green and white hair, the other guiding the scientist’s hand to his hard on, his eyes crossing and a hiss escaping between his teeth at the contact. 

“Good thing I’m a bottom, huh?” Gen gasped. 

“Yeah,” Senku breathed, rubbing a thumb against the mentalist’s head, bringing his mouth down to lick it as well. Both of them shuddered with pleasure, Gen at his partner’s hot tongue and slippery mouth, Senku at the moan the mentalist let loose. It wasn’t like anything Senku had heard before, his voice high and raspy and uncontrolled. 

Senku lowered his head further down and back up, the taste of pre-cum settling at the back of his throat. It wasn’t as gross as he was expecting, probably because it was Gen. If he was doing this with anyone else, he might be disgusted. The mentalist’s hands fumbled for Senku’s fingers and held them, hips thrusting slightly into the scientist’s open mouth. 

“Use your fingers, please,” Gen moaned, squeezing Senku’s fingertips. 

“Good thing I made some of this, then,” Senku said, standing to retrieve a bowl from a lower shelf. “Of course, lube isn’t a thing in this world. But, there’s something else that can be used instead.” 

Gen looked quizzically at the ceramic container. It was filled with a hard white substance that could look suspicious to someone unfamiliar with it. Senku dipped his fingers in, rubbing his fingers together and the substance turned into a clear liquid. The scientist couldn’t help but chuckle at Gen’s surprised expression. 

“Coconut oil,” he informed the mentalist. “It’s useful for many reasons.” 

“And what reason are we using it today, my scientist?” Gen purred, gaining more confidence. 

Senku took this as his invitation to kneel in front of the small mentalist, running both hands up his thighs and spreading his legs apart like a book. Gen’s breath hitched at the sudden contact, shutting his eyes. 

“I’ll be careful,” Senku whispered as he rubbed coconut oil on his fingers and around the area he was planning on entering. He slid one slender finger in without much resistance and Gen sighed in satisfaction. He slowly pushed it in and out, gaining momentum as he was egged on by the mentalist’s increasingly desperate sounds. 

‘Screw Lillian’s music. I could listen to this on repeat,’ Senku thought drunkenly. 

The scientist added two, then three fingers, watching as Gen became more and more out of control, writhing and whimpering on the desk, scattering the last of Senku’s notes to the wooden floor. 

“Why does this feel so good?” Gen asked, an arm draped over his heated face. 

“Because you have a prostate.” Senku couldn’t help adding a scientific fact in, helping Gen learn more about his body and, in turn, letting him know that Senku knew just what to do to make him feel good. 

“That’s why when I go like this,” Senku curled all three fingers inside Gen, making the mentalist cry out and arch his back off the table, “it makes you do that.” 

“Please,” Gen whined and Senku looked up. The mentalist looked absolutely wrecked, his snowy white fringe feathered out next to him, face red and sweaty, lips parted and panting for breath. Senku loved that he could make Gen (the man who could control his facial expressions better than anyone) come undone like this. 

“Please,” he repeated, rubbing a foot against Senku’s erection. “I want you. I want you so bad.” 

Senku easily stripped off his tunic and underwear, suddenly feeling a bit awkward. Seeing Gen completely naked on his desk was something of beauty, something you wanted to look at. But, Senku didn’t feel the same way about his body. He didn’t know why, but he felt it was something all scientists were cursed with: a low self-esteem. 

“You’re beautiful, Senku-chan,” Gen sighed, his eyes half-lidded and full of love. He lifted himself up a bit, running his fingertips over Senku’s now-muscular body. Working so diligently along with the villagers had been difficult, but his body was reaping the benefits, it seemed. Goosebumps rose upon Senku’s skin and he groaned. He couldn’t take any more of this teasing. 

Senku gently pushed Gen back down flat against the desk, lifting one of his thin legs to rest comfortably against the scientist’s shoulder. He guided his cock to Gen’s entrance and softly kissed his open mouth. 

“I didn’t believe love was made for me until I met you,” Senku said as he pushed lightly into Gen. The mentalist let out a noise somewhere between a gasp and yelp, tears pricking the corners of his wide eyes. 

“You… weren’t lying… when you said you were… bigger than me,” Gen breathlessly said, wincing at the pleasure and pain between them. 

Senku caught his tongue between his teeth as he rocked slightly forward, entering deeper millimeter by millimeter. 

“Mmn,” Gen moaned, rolling his eyes back in his head, hands grasping Senku’s hips as they moved faster and faster, gaining momentum and friction. 

Sex was another thing Senku had never really thought about. He was sure he’d never be able to engage in such an activity if there was no romantic connection and was completely fine with satisfying himself. But, Gen had completely changed that perception. Since realizing his feelings for Gen, Senku had fantasized about fucking the mentalist until it was the only thing that could get him off. But nothing, nothing, compared to the real thing. It was like comparing a written hypothesis with the actual experiment. 

“Do you want to flip over?” Senku asked, his own voice raspy. 

“No,” Gen said immediately, gripping harder onto the scientist’s hips. “I need to see your face.” 

Senku stopped thrusting and brushed a hand against Gen’s face, rubbing a thumb over the black crack on his left cheek. A sentimental smile spread across his face and thought to himself, ‘I need to see your face, too. What a stupid question, Senku.’ 

“Keep going,” the mentalist whimpered, pushing his pelvis down onto Senku, pulling a surprisingly loud moan from the scientist. 

That broke Senku completely. He leaned his body over Gen, squeezing a hand around his soft thigh, his other hand lacing through the mentalist’s on the desk. He grunted with every stroke, throwing his head back in ecstasy, his hips slapping against Gen in the most exhilarating way.

“Fuck…” he moaned and squeezed Gen’s hand. “I think I’m gonna cum soon.” 

“Uh-huh,” Gen looked up, his eyebrows drawn together, his lips trembling. “Me too.” 

Right as the words left the man under him, both of their abdomens tightened, that pressure and adrenaline collecting. Gen cried out, cinching his eyes shut, releasing all over his stomach and up to his chest. Senku pulled out and emptied himself, cum dribbling over his fingers and onto the floor. 

Instead of letting his legs give out, Senku leaned over and rested his feverish face against Gen’s chest, listening to his steadily calming heartbeat. 

“I love you,” Senku murmured into Gen’s skin. 

“Huh? I didn’t hear that.” Even though the scientist wasn’t looking, he could hear the smile in Gen’s voice. 

“I said that I love you. I really do. Now stop trying to embarrass me,” Senku said, rubbing his face into the mentalists chest. “I’m sure Chrome heard all of this and I’ll have to answer ten billion humiliating questions.”

Both arms wrapped around Senku, Gen’s face nestling itself into the scientist’s hair. “I love you, too,” he hummed happily.

**Author's Note:**

> I hope you liked it! I’ll be posting more parts to this later! Kudos and respectful comments are appreciated!
> 
> This is my [Twitter](https://mobile.twitter.com/lucadumpster)


End file.
